Former Health Minister Edwin Poots is demanding that the Public Prosecution Service immediately publishes a report into its decision not to prosecute Gerry Adams for withholding information about his paedophile brother, Liam.
Mr Poots said that the PPS "risked losing public confidence" if it didn't quickly release the material which has been in its possession for around a year.
"This is the gravest possible matter, it concerns the safety and welfare of children, and a senior politician disgracefully not passing on vital information in an abuse case for nine long years," he added.
He said the PPS's previous reason for not publishing the report - Liam Adams' outstanding appeal - no longer held as he lost his appeal last week.
The DUP MLA said he would be raising the issue as "very urgent business" at Thursday's Justice Committee meeting in Stormont.
A PPS spokeswoman last night said: "We are committed to publishing the report and it will be announced shortly."
After Liam Adams' conviction in 2013 for raping his daughter Aine, the Attorney General John Larkin began a review of the PPS's decision not to prosecute Gerry Adams for withholding information in the case.
Gerry Adams said that his brother confessed to him in 2000 that he had sexually abused Aine. But the Sinn Fein President did not report this to police for nine years.
Liam Adams was sentenced to 16 years in prison for raping and sexually abusing Aine from 1977 to 1983 from when she was four years old until she was nine.
Mr Poots said: "Liam Adams has been found guilty of the most serious child abuse at both his original trial and now appeal.
"There is grave public concern that Gerry Adams had information that could have brought this evil paedophile to justice years ago.
"Instead, the police were deprived of information which could have seen Liam Adams behind bars a lot sooner.
"We must immediately have access to the Attorney General's findings on the PPS's decision not to prosecute Gerry Adams.
"The PPS had previously indicated that it couldn't publish the report because of any impact it might have on Liam Adams' appeal of his conviction.
"Liam Adams lost his appeal last week. His legal proceedings have now concluded and there are no possible reasons for the PPS to continue letting dust gather on this report."
The Belfast Telegraph understands that the Attorney General's findings and a number of recommendations were forwarded to the PPS around a year ago.
Gerry Adams gave evidence for the prosecution during his brother's first trial in April 2013.
Untruths and evasions in Mr Adams' account of his dealings with his brother Liam were exposed under cross-examination.
That trial collapsed for unconnected legal reasons.
The prosecution decided not to call Gerry Adams as a witness during the second trial.
After four hours' deliberations, the jury found Liam Adams guilty of all 10 counts of sexual abuse by a majority of 11 to one.
Liam Adams did not appear in court for his appeal verdict last week but watched proceedings via video link from Maghaberry.
Neither he, nor his wife Bronagh who was in the public gallery, showed any emotion as his appeal was refused.
In their judgment, Lord Chief Justice Sir Declan Morgan, Lord Justice Gillen and Lord Justice Coghlin said: "The court has not been persuaded that the verdict of the jury was unsafe and, consequently, the appeal must be dismissed."